[16.14] NH$_3$ Emission in the Perseus Molecular Cloud Complex

E. F. Ladd (IfA), P. C. Myers, A. A. Goodman (CfA)

We present a survey for dense material around young IRAS sources in
the Perseus molecular cloud complex in the NH$_3$ (J,K) = (1,1) line
at 1.3 cm. NH$_3$ emission was detected in eight, and mapped in seven,
out of ten positions chosen for study. The dense cores found
typically have lower masses and narrower linewidths than cores
previously studied in Perseus, and are located near sources of lower
luminosity. NH$_3$ cores are found throughout the Perseus complex; however,
much of the detected dense gas is concentrated into two filamentary
``ridges'' located in the western part. As group, NH$_3$ cores in
Perseus have mean linewidth 0.6 kms$^{-1}$, radius 0.12 pc, kinetic
temperature 13 K, and mass 9 M$_\odot$. These mean values are larger
than the mean values for NH$_3$ cores with associated stars in Taurus,
but smaller than the mean values for cores associated with stars in
Orion A. Some of the cores in Perseus are ``thermally-dominated,''
with thermal and nonthermal linewidths similar to most Taurus cores,
while others are ``nonthermally-dominated,'' and are more similar to
the cores in Orion A. We conclude that the Perseus complex is
intermediate in its star forming potential betweeen the predominantly
low-mass star producing regions like Taurus and the regions capable of the
producing high mass stars such as Orion A.